A Question on Wind Turbines.

[Jim__]

There is a report in Science Daily that Rockport Missouri will get all of its electricity from wind turbines:

Rock Port, Missouri, First 100 Percent Wind-powered Community In U.S.

ScienceDaily (July 16, 2008) — Rock Port Missouri, with a population of just over 1,300 residents, has announced that it is the first 100% wind powered community in the United States. Four wind turbines supply all the electricity for the small town.


Rock Port’s 100% wind power status is due to four wind turbines located on agricultural lands within the city limits of Rock Port (Atchison County). The city of Rock Port uses approximately 13 million kilowatt hours of electricity each year. It is predicted that these four turbines will produce 16 million kilowatt hours each year.

Excess wind generated electricity not used by Rock Port homes and businesses is expected to be move onto the transmission lines to be purchased by the Missouri Joint Municipal Utilities for use in other areas.

A caller to Limbaugh on Wednesday (I know consider the source - but some of what he said sounds correct - Call Transcript) claimed that you can't get 100% of your power from wind, at least not without a large back-up system:

CALLER: Doesn't matter if there are four turbines or 4,000 turbines. It's complete baloney.

...

CALLER: It's not physically possible. Well, in the first place you'd have to have strong winds at all times, 24/7, 365. This occurs almost no place on earth. Maybe at the top of Mt. Everest, perhaps. At best, 30% of the time anywhere in the civilized world. So without that you'd have to have another source of electricity during the other 70% of the time which comes from conventional sources both gas, nuclear.

...

CALLER: Well, the turbines are powered by wind, but when the wind is isn't blowing, they don't produce any electricity -- and although most people don't know it, don't realize it, there's no storage on the grid. There's no possible way to store that kind of electricity. There are no batteries large enough. So this is the fatal flaw of wind energy. It requires fossil fuel backup of at least 90% of the installed capacity of whatever the windmills are.

If your power is generated by wind, do you always have to have a back up system with almost the same capacity as the wind turbines?

[jpak]

1. Place blowhard/gasbag Limbaugh next to the turbines and you will get 100% capacity

from those turbines....

[izquierdista]

2. To be entirely correct

You would have to have a large storage system for the 70% of the time that the wind is not blowing.

He is wrong when he claims that there are no batteries large enough. That is not the only way to store energy. You can pump water uphill and reclaim the energy when it falls back down. You can have fuel cells store it as hydrogen. You can turn it to heat and store it that way.

[jpak]

8. Wind farms produce electricity 65-90% of the time - not 30% of the time

They have average nameplate capacity factors of ~30%.....ex. a 3 MW turbine will have an average output of 1 MW but will produce electricity 65-90% of the time...

AEP is installing 1000 MW of NaS batteries to support wind farms in their service area.

[DCKit]

3. Their "backup" is the grid they're connected to.

When they have a surplus, it'll go to the grid. When they need extra electricity, they'll take it back.

They should be able to tell from the weather forecast when to expect they'll need outside supplies and that will give their outside supplier time to spin up their gas turbines.

[One_Life_To_Give]

4. In simple terms yes you need a backup

Over an area/region there will be times when the wind is not blowing enough for the turbines to generate any power and frequently they will not be able to generate full rated power.

Concider the town of Rockport cited above. If I added perhaps a Pumped Storage facility (used now by utilities for similar purposes) and spent the 16Million KWHR each year to put water into the reservoir. I could extract the 13Million KWHR as the town needed it by releasing water thru the generators. Now there are some perhaps better desings being drawn up and tested. But at the moment we don't have nearly enough of these to fill the need. What the grid operators do is to keep a spinning reserve of generators (fossile fueled) online ready to absorb any load fluctuations.

[liberal N proud]

5. It all depends on the sustainable wind

I lived about 30 miles from Rock Port for many years. The area does have wind capable of producing enough power.

Here is a wind speed chart for Missouri. Rock Port is located in the far northwest corner of the state.



http://www.eere.energy.gov/windandhydro/windpoweringamerica/where_is_wind_missouri.asp

Rock Ports sits on top of the Missouri River bluffs where the winds from the southwest, west and northwest have nothing to slow them down. The wind blows most of the time in Northwest Missouri.


Here is some FAQ on a different wind generation system that might help as well.
http://www.massmegawatts.com/faqs.htm

[Jim__]

6. Thanks for the answers. It sounds like you need a back up, but ...

... the power generated by the wind turbines can be used to power a back-up, like pumping water up hill for later usage.

[phiddle]

7. They probably use so-called "net-metering".

All electricity generated by the wind turbines is fed into the grid. Each citizen gets credit for his/her portion of the electricity generated. On the year this would average 16 million Kwh/1,300persons or approx 1,240 Kwh per consumer. If a person used more than this, he/she would be charged, if less, then Missouri Joint Municipal Utilities would buy the difference between 1240 and the amount used. Since the town uses an aggregate of 13 million KWH/year, but generates an aggregate of16 million KWh, feeding it into the grid, it is accurate to say that they generate enough for their own needs.

[caraher]

9. Sure, you do need additional capacity to supplement variable sources

but 100% is rubbish - that implies zero reliability for the wind, which is absurd. The amount you need depends on a lot of factors - and as noted, batteries are neither the only nor necessarily the best way to store energy for off-peak production hours.

The grid you connect to is important. While the wind rarely blows steadily at a single location 24/7, it's also true that if there's less wind than average in one location there's almost certainly more wind than average somewhere else. with sufficiently robust management a large array of unsteady power sources adds up to an overall system with a pretty reliable and predictable overall output. There are some engineering challenges associated with making the grid stable against fluctuations, but they're scarcely showstoppers. And even if, in the end, you need to maintain some gas-fired plants you can take on and offline quickly, you're still ahead using that to fill in the gaps for production fluctuations with renewables versus simply building more fossil-fuel based generation capacity.

[Enthusiast]

10. Republicans are pushing nuclear.

Apparently their masters have a substantial amount of money invested in that technology. This is the reason they discount better resources like wind and solar. This is very obvious to me. Just follow the money. McCain is fully on board with nuclear.

[HamdenRice]

11. I second, third and fourth all the "grid" comments. Few people seem to understand this.

At one time in my life when I worked in finance, I drafted power plant supply agreements (among other documents involved in setting up power plants).

When a town says they are self-sufficient in wind electricity, it doesn't mean they are autarchic -- ie isolated and producing only for themselves consuming only what they produce. It means that they produce economically the same amount of electricity they consume.

Electricity is not like bushels of corn or cars -- goods that can be traced from source to consumer. It is fungible beyond fungible.

A particular plant of any kind almost always sells that power onto the grid, which is regional and even national in scope. Consumers in a particular location draw electricity from the grid. But that doesn't mean there is anyway to trace the electricity consumed in Rockport to the windmill in Rockport.

The same is true of carbon based plants. Sometimes they produce more power than is locally consumed and sell it onto the grid, and sometimes they don't and the locality buys power from the grid.

So the backup is the grid, and when it's windy, Rockport windmills sell more power onto the grid than they use. If their deficits and surpluses balance, it's fair to say they produce all the electricity they use by wind. But more precisely they produce as much electricity by wind as they consume.

This is not a problem at all for towns going green. They don't need storage batteries. I suppose the only real objection to their claim and the only valid objection the caller is making is that at present, on a national scale, if everyone tries to go to wind, solar, tidal and hydroelectric, we might need some carbon based plants.

But keeping in mind there is a national grid, I find it hard to believe there are going to be times when it is not sunny or windy anywhere, all the dammed rivers are dry, and the tides have all ceased.

It's the grid. Not the plant.